M5.4 earthquake 136 km WNW of Neiafu, Tonga
A magnitude 5.4 earthquake struck 136 km WNW of Neiafu, Tonga on Fri, Sep 18, 1987, 10:24 AM GMT+13 (21:24 UTC), 253 km (157 mi) below the surface.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 5.4 (Mw, moment), moderate
- Magnitude from
- USGS National Earthquake Information Center
- Local time
- UTC
- 1987-09-17 21:24:52 UTC
- Depth
- 252.5 km (156.9 mi), intermediate-depth
- Epicenter
- 18.412° S, 175.249° W
- Region
- Tonga
- Tsunami flag
- No
- Status
- Reviewed by a seismologist
Magnitude estimates
Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.
| Mag. | Scale | Computed by | Notes |
|---|---|---|---|
| 5.4 | Mw, moment | USGS National Earthquake Information Center | Preferred · Reviewed |
| 5.41 | Mw, moment | ISC-GEM global catalog | Final · ±0.1 |
| 5.4 | Mwc, centroid moment | Global CMT project | Preliminary |
What happened
The USGS’s account of the effects of this earthquake.
CENTROID, MOMENT TENSOR (HRV) Data Used: GDSN L.P.B.: 16S, 32C Centroid Location: Origin Time 21:24:58.4 0.5 Lat 18.48S 0.05 Lon 175.30W 0.06 Dep 246.1 2.3 Half-duration 2.0 Moment Tensor; Scale 10**17 Nm Mrr=-0.31 0.05 Mtt=0.59 0.08 Mff=-0.28 0.09 Mrt=-0.83 0.07 Mrf=-1.28 0.07 Mtf=0.30 0.08 Principal Axes: (T) Val=1.63 Plg=37 Azm=141 (N) Val=0.01 Plg=18 Azm=37 (P) Val=-1.65 Plg=48 Azm=286 Best Double Couple:Mo=1.6*10**17 NP1:Strike=289 Dip=19 Slip=-18 NP2:Strike=35 Dip=84 Slip=-108
From the USGS event page for usp00038fw. U.S. Geological Survey text and figures are in the public domain.
Did you feel it?
No one has reported feeling this quake to the USGS.
How well it is located
Reviewed by a seismologist.
- Depth from
- FROM_LOCATION
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 2.4 and up: 0 in the 60 days after this one and 0 in the 30 days before it.
None recorded.
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Sources
From the USGS Earthquake Hazards Program and its partner networks, event usp00038fw (also filed as gcmtb091787b, gcmt19870917212452, iscgem457835). Read Mon, Oct 5, 2026, 5:19 AM UTC.